Method and apparatus for pressing fibrous tubing



April 28, 1959 A. R. TAYLOR METHOD AND APPARATUS FOR PRESSING FIBROUS TUBING Filed Dec. 5. 1955 2 Sheets-Sheet 1 INVENTOR. BY flifiari 2,884,062 METHOD AND APPARATUS FOR PRESSING FIBROUS TUBING Filed Dec. 5. 1955 ii|s SISISII 5,;

2 Sheets-Sheet 2 April 28, 1959 lsi ' IN VEN TOR. Marl ]&

United States Patent NIETHOD AND APPARATUS FOR PRESSING FIBROUS TUBING Arthur R. Taylor, Berlin, NH, assignor to Brown Company, Berlin, N .H., a corporation of Maine 4 Application December 5, 1955, Serial No. 551,044

6 Claims. (Cl. 162-415) This invention relates to the manufacture of fibrous tubing from wet pulp .and pertains more specifically to apparatus for progressively pressing and compacting successive portions of the tubing while the fiber is still wet against a forming mandrel to express a portion of the "water therefrom.

In the manufacture of fibrous pipe such as the type commonly employed as soil pipe a wet lap or sheet of suitable fibers is made on a Fourdrinier wire or in any other suitable manner and is then wrapped while still wet about a forming mandrel, dried either on the mandrel or after removal from the mandrel by heating itin an oven or the like, and impregnated with a suitable water-repellent or waterproofing material such as asphalt, pitch, or the like.

The drying step in such a process is normally of prolonged vduration because of the relatively large amount of water which must be removed from the pipe wound from the wet sheet or lap, the time required being of the order of fifteen hours or more even at elevated temperature. Accordingly, in order to attain a given output of such pipe, there is required both a very large oven capacity and a large number of forming mandrels. Furthermore, the dried fibrous pipe or tubing produced in this fashion is uncompacted and highly porous so that it absorbs a large quantity of waterproofing agent during the impregnating step.

.One object of the present invention is to provide an apparatus for progressively pressing and compacting successive portions of wet fibrous tubing upon a forming mandrel.

Another object is to provide for advancing or conveying forming mandrels covered with a layer of 'wet fiber and progressively pressing and compacting successive portions of the fibrous layer as it advances.

Y Still a further object is to provide apparatus for rapidly and efficiently reducing the water content of wet fibrous tubing in a continuous manner while still on its forming mandrel.

Still another object is to provide for compacting and densifying wet. fibrous tubing while simultaneously conveying it to a subsequent operation.

Other and further objects will be apparent from the drawings and from the description which follows.

In the drawings:

Fig. 1 is a plan view partly broken away showing one embodiment of the present invention;

Fig. 2 is a view in side elevation;

Fig. 3 is a view in vertical section along the line 3-3 of Fig. 2;

Fig. 4 is a view in vertical section along the line 4-4 of Fig. 2;

Fig. 5 is a view in vertical section along the line 5--5 of Fig. 2;

Fig. 6 is a view in vertical section along the line 6-6 of Fig. 2;

Fig. 7 is a view in section on an enlarged scale along the line 7-7 of Fig. 2; and

- Fig- 8 is a view in section along the line 88 of Fig. 7.

Referring to the drawings, the apparatus includes an endless flexible perforate or porous conveyor belt 10 mounted on a pair of spaced pulleys 12, 14, mounted 'ice j on drive shafts 13, 15, one or both of which may be driven from any suitable power source (not shown). Conveyor belt 10 may suitably comprise a woven or braided belt of textile material such as nylon pervious to water and having a moderate amount of flexibility and extensibility. The elongated forming mandrels 16, 16 carrying on their outer face a layer of wet fibrous lap or sheet 18 may be supplied to the upper reach of belt 10 from any suitable source and are advanced by the belt from left to right as seen in Figs. 1 and 2.

Intermediate main drive pulleys 12, 14 there is pro vided means for wrapping or enfolding belt 10 about mandrels 16, 16 carrying pulp layers 18, 18. The wrapping or enfolding means includes supporting rollers 20, 22, 24 provided with concave surfaces. In addition, there are provided adjacent intermediate supporting roller 22 a pair of vertically mounted concave rollers 26, 28 at each side of the advancing mandrels, and immediately above the last supporting roller 24 is mating roller 30. All of these rollers may conveniently be idler rollers although in some cases, depending upon the size and weight of forming mandrels 16, it may be desirable to provide driving means for driving one or more of these rollers.

Adjacent the aforesaid wrapping rollers and in a position to engage the mandrels wrapped in belt 10 as they advance is a pressing device indicated generally by the numeral 34. The pressing device includesa generally cylindrical frame member 36 (Fig. 6) through which the advancing belt passes. Mounted at opposite ends of frame 36 are pairs of sprockets 40, 40, each pair of sprockets carrying an endless chain 42, the Working reach of which extends inwardly of frame member 36 for movement with advancing belt 10, the return reach 1y.- ing outside of frame 36. Sprockets 40, 40 mounted on shafts 41, 41 may be idler sprockets just as the wrapping rollers are or, if desired, they may serve as driving means, being driven by any suitable means (not shown) at approximately the same speed as the advancing belt 10. Mounted on the links of each of endless chains 42 are a plurality of pressing members 44, 44 provided with an arcuate pressing face 46 which conforms to the outer surface of belt 10 Wrapped on fibrous layer 18 which in turn is supported by forming mandrel 16. The individual pressing segments 44, 44 are arranged so that their front and rear margins are adjacent each other in the straight reach of chain, as seen in Fig. 7, thus forming with the chain an endless band. In addition, the pressing segments mounted on each adjacent chain, as seen in Fig. 6, are so arranged that their lateral margins are adjacent each other, all of the pressing segments together mating in the working reaches of chains 42 to form a hollow chamber 43 engaging the outer face of belt 10. Mounted on casing 36 adjacent the working reach of each band is a supporting rail 48, cam means 50 being provided for adjustably moving rail 48 toward and away from mandrel 16. The terminal portions 52, 54 at each end of the working face of rails 48 slope gradually inwardly toward mandrel 16, as best seen in Fig. 7, so that chain 42 carrying pressing segments 44 is urged gradually inwardly as it advances over terminal portion 52 to bring the pressing segments into pressing engagement with belt 10 as the belt with its enfolded mandrel and fibrous tubing advances through the pressing member 34. Similarly, as segments 44 advance over the opposite terminal portion 54 toward sprocket 40, they are released from the tubing enfolded in belt 10. Each pressing segment 44 is protions 56.-

In operation of the device, mandrels 16 carrying a layer of wet fiber 18 are placed endwise on advancing conveyor belt 10. As the belt carrying the mandrels advances over and through the Wrapping rollers 20, 22, 24, 26, 28, 30, belt is bent progressively around the mandrel and fibrous tubing 18, as seen in Figs. 3, 4 and 5, until the mandrel and tubing are substantially completely enveloped by the belt. As the mandrel carrying the wet fibrous layer enveloped in the belt continues to advance through pressing member 34, the endless bands comprising pressing segments 44, 44 come into engagement with successive portions of belt 10, and as chains 42 ride up over sloping end portions 52 of rails 48, pressing segments 44 are gradually pressed against the belt, exerting the desired amount of pressure on the wet fibrous layer 18 and expressing water therefrom through the perforate fabric belt 10 and through the perforations 56, 56 of the pressing segments. Belt 10 continuing to advance with the enfolded mandrel 16, the fibrous layer 13 is compacted and densified. As belt 10 leaves pressing member 34, it automatically unfolds gradually as it advances toward pulley 14, leaving mandrel 16 together with the now compacted and densified fibrous layer 18 free to be removed.

It will be apparent that the foregoing construction is readily adjustable to accommodate various sizes of mandrel and various thicknesses of tubing, the conveyor belt 10 in each case preferably having a width at least as great as, preferably greater than, the outer periphery of the tubing so that the tubing is completely enveloped by the belt as it passes through the pressing member 34. Although only a single belt is shown in the drawings, it will be understood that two or more belts arranged with overlapping margins may be employed. The presence of belt 10 between the layer of fibrous tubing 18 and the pressing segments 44, 44 permits considerable latitude in the spacing between the lateral margins of pressing segments 44 mounted on adjacent chains 42, 42 since belt 10 serves to bridge any gap between the margins of pressing segments 44, 44. In addition, since chain rails 48, 48 are adjustably mounted for movement toward and away from the mandrels, the pressure applied to the wet fibrous tubing may likewise be readily adjusted to obtain the desired degree of compacting or densification and to remove the desired proportion of water.

By increasing the pressure, which normally ranges from 35 to 55 pounds per square inch on the wet fibrous tubing, the extent of densification and compacting may be increased to the point where the dried tubing absorbs substantially less waterproofing agent than does the same tubing dried in the conventional manner in the absence of pressure.

Although specific embodiments of the invention have been described herein, it is not intended to limit the invention solely thereto, but to include all of the obvious variations and modifications within the spirit and scope of the appended claims.

I claim:

1. Apparatus for pressing and compacting wet fibrous tubing upon an elongated forming mandrel comprising a plurality of mating pressing segments together forming a hollow chamber embracing said tubing on said mandrel, each segment having a perforate face and being mounted for movement in a direction along the length of said mandrel and for movement toward and away from said mandrel, and means for moving each said segment toward and away from said mandrel to press and compact said wet fibrous tubing and express water therefrom through said perforate faces and for moving all of said segments together in a direction along the length of the mandrel while pressing against said tubing to advance said mandrel and tubing in the direction of its length.

2. Apparatus as defined in claim 1 comprising in addition an endless flexible water-pervious conveyor belt for carrying said tubing on said mandrel through said hollow chamber, the width of said belt being at least as great as the outer periphery of said tubing, means for wrapping said belt about the tubing on the mandrel to envelop the same prior to its passage through said chamber, and means for advancing said belt through said chamber.

3. Apparatus for progressively pressing and compacting wet fibrous tubing upon an elongated forming mandrel comprising an endless flexible conveyor belt pervious to water for supporting and advancing said tubing on said mandrel, said belt having a width at least as great as the outer periphery of said tubing, means for advancing said belt, means for wrapping said belt about said tubing and mandrel to envelop the same completely as it advances, and pressing means for pressing and compacting said wet fibrous tubing against said mandrel while advancing, enveloped by said belt to express water therefrom through said belt, said pressing means comprising a plurality of endless flexible pressing elements, each having a reach extending generally in the direction of travel of said belt, said pressing elements being mounted around said belt to form together a hollow chamber through which the belt passes with each said reach in position to press and compact said wet tubing on the mandrel while enveloped by the belt, and means for advancing each said reach in the direction of travel of said belt.

4. Apparatus for progressively pressing and compacting wet fibrous tubing upon an elongated forming mandrel comprising an endless flexible conveyor belt pervious to water for supporting and advancing said tubing on said mandrel, said belt having a width at least as great as the outer periphery of said tubing, means for advancing said belt, means for wrapping said belt about said tubing and mandrel to envelop the same completely as it advances, and pressing means for pressing and compacting said wet fibrous tubing against said mandrel while advancing enveloped by said belt to express water therefrom through said belt, said pressing means comprising a plurality of rails arranged about and generally parallel to said belt, a plurality of endless bands each comprising a series of flexibly connected individual pressing segments having perforate pressing faces, each band having an operative reach slidably mounted on one of said rails and a return reach remote from said belt, the segments of all of said bands in their operative reaches forming together a hollow chamber and pressing said fibrous tubing on the mandrel enveloped by the belt as it advances therethrough, and means for advancing the operative reaches of said bands in the same direction and at approximately the same speed as said belt.

5. Apparatus as defined in claim 4 in which the working surface of each rail slopes inwardly toward the belt adjacent the entrance end of said hollow chamber to cause the segments in each operative reach to press and compact the tube with increasing pressure as it enters the pressing means.

6. Apparatus as defined in claim 4 in which the working surface of each rail slopes inwardly toward the belt adjacent the entrance end of said hollow chamber and outwardly from the belt adjacent the exit end to cause the segments in each operativevreach to press and compact the tube with increasing pressure as it enters the pressing means and with decreasing pressure as it leaves.

References Cited in the file of this patent UNITED STATES PATENTS 469,663 Greenfield Feb. 23, 1892 556,857 Madden Mar. 24, 1896 1,399,087 Seigle Dec. 6, 1921 1,494,345 Eaid May 20, 1924 1,497,344 Parker June 10, 1924 1,719,819 Koppelman July 2, 1929 i 1,984,073 Mazza Dec. 11, 1934 2,101,921 Shaver Dec. 14, 1937 2,649,133 Just Aug. 18, 1953 2,720,142 Magnani Oct. 11, 1955 2,796,810 Muller June 25, 1957 

